For the lighting and marking of aircraft taxiways light sources are required which have a low mounting height and emit a beam of rays, as parallel as possible as a general rule, in a predefined direction. On account of the comparatively small glass envelope, a long service life and a high light yield, halogen incandescent lamps are preferably employed in this situation, the light from which is focused by means of a reflector and radiated directionally. It is however also conceivable to employ high-pressure discharge lamps. For the sake of simplicity, halogen incandescent lamps with a spiral-wound filament are assumed in the following, whereby high-pressure discharge lamps with an electric arc should however also be included.
A precise positioning of the light source, in other words of the filament or the arc, within the reflector environment is necessary for focusing the light. Production tolerances in the manufacture of the lamp glass envelope would require a complex readjustment following installation of the lamp in order to achieve precise positioning at the focal point of the reflector environment. In order to avoid this problem, the base of each individual lamp glass envelope is actually adjusted to the eventual focus position in the reflector during the assembly of the lamp. In the case of a defective lamp, the entire module comprising glass envelope and base is replaced and no readjustment is needed. For this so-called “airfield” sector, special halogen incandescent lamps (and in terms of this invention also high-pressure discharge lamps) are therefore employed, wherein electrical connecting cables are incidentally connected to contact pins led out of the actual lamp glass envelope. In addition, the invention is however also directed at lamps of comparable construction for other fields of application, whether it be for fitting in reflector housings also preferably coming into consideration outside the airfield sector, or whether it also be independent thereof.